Composition comprising macrocyclic tetra-amido metal complex as bleaching catalyst

ABSTRACT

The present invention provides a laundry bleaching composition comprising: a) a macrocyclic tetra amido N-donor metal-ligand complex (preferably, 5,6-benzo-3,8,11,13-tetraoxo-2,2,9,9,12,12-hexamethyl-1,4,7,10-teraaza-cyclo-tridecane), and b) an alkyl benzene sulphonate surfactant said composition being substantially devoid of any added peroxygen bleach or a peroxy-based or peroxyl-generating bleach system.

TECHNICAL FIELD

The present invention relates to compositions comprising a macrocyclictetra-amido N-donor metal-ligand complexes as a bleaching catalyst.

BACKGROUND OF THE INVENTION

Oxidation catalysts comprising metal-complexes are well known. Suchcatalysts have been proposed for use in laundry compositions ascomponents of a bleaching system. These catalysts activate H₂O₂ or otherperoxygen sources.

A particular catalyst is disclosed in WO 98/03263, filed 21 Jul. 1997,(Collins et al.), which comprises a macrocyclic (tetra) amido N-donor.The macrocycle is capable of complexing with a metal ion, for example aniron III or IV. The complex also comprises axial ligands and one or morecounter ions.

One proposed purpose of these catalysts has been to assist in thebleaching of dyestuffs released from articles being laundered. If thesedyestuffs are not removed from the wash liquor then they will re-depositonto articles and cause a loss of colour definition or even catastrophicdamage to ‘white’ articles. U.S. Pat. No. 5,853,428, filed 24 Feb. 1997,(Collins et al.) discloses use of similar catalysts in laundry detergentcompositions. In both these citations the addition of hydrogen peroxide,or a source thereof, is envisaged as a means of activating the catalyst.

Bleaching agents typically present in laundry detergents includepercarbonates and/or perborates, which can also act as sources ofhydrogen peroxide and/or other peroxyl species.

Bleaching catalysts capable of bleaching effectively in the absence ofadded peroxyl sources have recently become the focus of some interest,for example: WO9965905; WO0012667; WO0012808; WO0029537, and, WO0060045.It is believed that these catalysts have the capability to useatmospheric oxygen as a source of oxidising equivalents.

SUMMARY OF THE INVENTION

Surprisingly, we have found that dyes can be decolourised by amacrocyclic tetra amido N-donor metal-ligand complex in the absence ofadded hydrogen peroxide provided that a commercial alkyl benzenesulphonate surfactant is present.

Accordingly, the present invention provides a bleaching compositioncomprising:

-   a) a macrocyclic tetra amido N-donor metal-ligand complex, and,-   b) an alkyl benzene sulphonate surfactant.    said composition being substantially devoid of any added peroxygen    bleach or a peroxy-based or peroxyl-generating bleach system.

It is particularly advantageous to be able to bleach dyestuffs withoutthe addition of hydrogen peroxide or a source thereof to thecomposition. Not only does this have savings in terms of cost, but italso removes some of the limitations on formulation which would bebrought about by the presence of hydrogen peroxide.

The mechanism of the invention is not fully understood. While bleachingoccurs (in the absence of added hydrogen peroxide) in the presence of analkyl benzene sulphonate (ABS) surfactant, it does not occur if the ABSis replaced with an ethoxylated alcohol nonionic surfactant. It isunclear whether some component of the ABS is acting as a primarysubstrate for the catalyst or whether the oxidising equivalents areeventually derived from atmospheric oxygen.

A possible explanation is that relatively slow air oxidation of ABSleads to the formation of hydroperoxides. In the presence of thecatalyst these act as a substrate enabling the oxidation of dyestuffs.The term “substantially devoid of any added peroxygen bleach or aperoxy-based or peroxyl-generating bleach system” should therefore beconstrued within the spirit of the invention. It is preferred that,other than as a component of the surfactant, the composition has as lowa content of peroxyl species present as possible.

The present invention extends to a method of bleaching a substratecomprising applying to the substrate, in an aqueous medium, thebleaching composition according to the present invention.

The present invention extends to a commercial package comprising thebleaching composition according to the present invention together withinstructions for its use.

The bleaching composition may be contacted to the textile fabric in anysuitable manner. For example, it may be applied in dry form, such as inpowder form, or in a liquor that is then dried, for example as anaqueous spray-on fabric treatment fluid or a wash liquor for laundrycleaning, or a non-aqueous dry cleaning fluid or spray-on aerosol fluid.

Any suitable textile that is susceptible to bleaching or one that onemight wish to subject to bleaching may be used. Preferably the textileis a laundry fabric or garment.

In a preferred embodiment, the method according to the present inventionis carried out on a laundry fabric using an aqueous treatment liquor. Inparticular, the treatment may be effected in a wash cycle for cleaninglaundry.

The bleaching method may be carried out by simply leaving the substratein contact with the bleaching composition for a sufficient period oftime. Preferably, however, the bleaching composition is in an aqueousmedium, and the aqueous medium on or containing the substrate isagitated.

In a particularly preferred embodiment the method according to thepresent invention is carried out on a laundry fabric using aqueoustreatment liquor. In particular the treatment may be effected in, or asan adjunct to, an essentially conventional wash cycle for cleaninglaundry. More preferably, the treatment is carried out in an aqueousdetergent wash liquor. The bleaching composition can be delivered intothe wash liquor from a powder, granule, pellet, tablet, block, bar orother such solid form. The solid form can comprise a carrier, which canbe particulate, sheet-like or comprise a three-dimensional object. Thecarrier can be dispersible or soluble in the wash liquor or may remainsubstantially intact. In other embodiments, the bleaching compositioncan be delivered into the wash liquor from a paste, gel or liquidconcentrate.

A unit dose as used herein is a particular amount of the bleachingcomposition used for a type of wash. The unit dose may be in the form ofa defined volume of powder, granules or tablet.

DETAILED DESCRIPTION OF THE INVENTION

In order that the invention may be further understood it is describedbelow with reference to certain preferred features.

The Surfactant:

As noted above, the surfactant comprises an alkyl benzene sulphonate.Suitable alkyl benzene sulphonate compounds which may be used arewater-soluble alkali metal salts of organic sulphonates having alkylradicals containing from about 8 to about 22 carbon atoms, the termalkyl being used to include the alkyl portion of higher acyl radicals.Particularly preferred surfactant compounds are sodium and potassiumalkyl C₉-C₂₀ benzene sulphonates, particularly sodium linear secondaryalkyl C₁₀-C₁₅ benzene sulphonates. The most preferred anionic detergentcompounds are sodium C₁₁-C₁₅ alkyl benzene sulphonates.

Other surfactants may be present in the compositions of the invention.Preferably these are anionic surfactants. Examples of suitable syntheticanionic surfactants include:

-   -   sodium and ammonium alkyl sulphates, especially those obtained        by sulphating higher (C₈-C₁₈) alcohols produced, for example,        from tallow or coconut oil;    -   sodium alkyl glyceryl ether sulphates, especially those ethers        of the higher alcohols derived from tallow or coconut oil fatty        acid mono-glyceride sulphates and sulphonates;    -   sodium and ammonium salts of sulphuric acid esters of higher        (C₉-C₁₈) fatty alcohol alkylene oxide, particularly ethylene        oxide, reaction products;    -   the reaction products of fatty acids such as coconut fatty acids        esterified with isethionic acid and neutralised with sodium        hydroxide;    -   sodium and ammonium salts of fatty acid amides of methyl        taurine;    -   alkane mono-sulphonates such as those derived by reacting        alpha-olefins (C₈-C₂₀) with sodium bisulphite and those derived        by reacting paraffins with SO₂ and Cl₂ and then hydrolysing with        a base to produce a random sulphonate;    -   sodium and ammonium (C₇-C₁₂) dialkyl sulphosuccinates; and;    -   olefin sulphonates, which term is used to describe material made        by reacting olefins, particularly (C₁₀-C₂₀) alpha-olefins, with        SO₃ and then neutralising and hydrolysing the reaction product.

Preferred levels of anionic surfactant are 1-30% wt on product,preferably 3-10% wt on product.

The compositions of the invention may also comprise nonionicsurfactants. As will be discussed below, the nonionic surfactants do notappear to act as substrates for the catalyst. Moreover, it is believedthat even in the presence of anionic surfactant the catalysts becomeless effective as the level of nonionic is increased. However low levelsof nonionic surfactants can be present to confer cleaning benefits.

Preferably, the level of nonionic surfactant in the composition is lessthan 5% wt.

Examples of suitable nonionic surface-active compounds which may beused, preferably together with the anionic surface-active compounds,include, in particular;

-   -   the reaction products of alkylene oxides, usually ethylene        oxide, with alkyl (C₆-C₂₂) phenols, generally 5-25 EO, i.e. 5-25        units of ethylene oxides per molecule; and;    -   the condensation products of aliphatic (C₈-C₁₈) primary or        secondary linear or branched alcohols with ethylene oxide,        generally 2-30 EO.

Other so-called nonionic surface-actives include alkyl polyglycosides,sugar esters, long-chain tertiary amine oxides, long-chain tertiaryphosphine oxides and dialkyl sulphoxides.

Preferably the surfactant is present in the composition in an amountsuch that a unit dose provides at least 0.05, more preferably 0.1, mostpreferably 0.2 g/l concentration of the surfactant compound in a wash.

The Bleach Catalyst:

The amount of catalyst in the detergent composition is typicallysufficient to provide a concentration in the wash liquor of generally0.005 μm to 100 μm, preferably from 0.025 μM to 50 μM, more preferablyfrom 0.05 μM to 10 μM.

Preferred ligands are un-bridged tetra-amido complexes.

Preferred metal-complexed ligands are those having the structure asshown in general formula 1:

wherein:

-   -   B₁, B₃ and B₄ each represent a bridging group having zero, one        two or three carbon containing nodes for substitution, and B₂        represents a bridging group having at least one carbon        containing node for substitution, each said node containing a        C(R), C(R₁)(R₂) or C(R)₂,    -   each R substituent is the same is the same or different from the        remaining R substituents, and        -   (i) is selected from the group consisting of alkyl, alkenyl,            cycloalkyl, cycloalkenyl, aryl, alkynyl, alkylaryl, halogen,            alkoxy, phenoxy and combinations thereof, or        -   (ii) form a substituted or unsubstituted benzene ring of            which two carbons on the ring form nodes in the B-unit;    -   M is a transition metal ion;    -   L is an axial ligand; and,    -   Q is an alkali metal or tetra-alkyl ammonium or tetra-phenyl        phosphonium counter-ion.

Preferably, the axial ligand is selected from the group consisting ofwater and halide. Particularly preferred axial ligands are water andchloride.

It is within the scope of the present invention to have a bleachactivator, wherein M is selected from the group consisting of Fe, Mn,Cr, Cu, Co, Ni, Mo, V, Zn and W.

The most preferred catalyst is that in which the ligand is5,6-benzo-3,8,11,13-tetraoxo-2,2,9,9,12,12-hexamethyl-1,4,7,10-tetraaza-cyclo-tridecane.

The axial ligand ‘L’ is water or preferably chloride. The counter-ion‘Q’ is preferably lithium. The ligand is also known as3,4,8,9-tetrahydro-3,3,6,6,9,9-hexa-methyl-1H-1,4,8,11-benzotetraazocyclotridecane-2,5,7,10(6H,11H) tetrone.

In addition to the catalyst it is possible to include an enhancer in thecomposition. Preferably the enhancers are nitrogen-containing organicmolecules. More preferably, the enhancer compounds are of the generalformula one, shown below:

wherein:

-   -   Z₁ and Z₂ are electron-withdrawing groups, independently        selected from the group consisting of optionally substituted        alkyl/(hetero) (poly)aryl-, -sulfone, -sulfoxide, -sulfonate,        -carbonyl, -oxalyl, -amidoxalyl, -hydrazidoxalyl, -carboxyl and        esters and salts thereof, -amidyl, -hydrazidyl, and nitrile.    -   Z₃ and Z₄ are hydrogen, or are absent when the bonding between        Z₁ or Z₂ and the adjacent nitrogen in the general form is a        pi-bond.

In preferred enhancers Z₃ and Z₄ are both hydrogen (thereby forming ahydrazino compound), or Z₃ and Z₄ are both absent (thereby forming anazino compound).

Particularly preferred azino enhancers are molecules of the generalformula given below:

This molecule is known as2,2′-Azino-bis(3-ethyl-benzthiazoline-6-sulphonate) diammonium salt. ItsCA registry number is 30931-67-0.

Preferred hydrazino enhancers may contain one or more than one of thehydrazino structures. The general formulae of two particularly preferredenhancers are given below:

The structure of a further enhancer, which does not have thecharacteristic azino- or hydrazino-bond of the preferred embodimentsdiscussed above is given below:

This is phenothiazine-10-propionate (PTP), as described in U.S. Pat. No.5,451,337 and U.S. Pat. No. 5,445,755.

Other Components:

The composition may also contain a detergency builder, for example in anamount of from about 5 to 80% by weight, preferably from about 10 to 60%by weight. Builder materials may be selected from 1) calcium sequestrantmaterials, 2) precipitating materials, 3) calcium ion-exchange materialsand 4) mixtures thereof.

Examples of calcium sequestrant builder materials include alkali metalpolyphosphates, such as;

-   -   sodium tripolyphosphate;    -   nitrilotriacetic acid and its water-soluble salts;    -   the alkali metal salts of carboxymethyloxy succinic acid,        ethylene diamine tetraacetic acid, oxydisuccinic acid, mellitic        acid, benzene polycarboxylic acids, citric acid; and;    -   polyacetal carboxylates as disclosed in U.S. Pat. No. 4,144,226        and U.S. Pat. No. 4,146,495.

Examples of precipitating builder materials include sodiumorthophosphate and sodium carbonate.

Examples of calcium ion-exchange builder materials include the varioustypes of water-insoluble crystalline or amorphous aluminosilicates, ofwhich zeolites are the best known representatives, e.g. zeolite A,zeolite B (also known as zeolite P), zeolite C, zeolite X, zeolite Y andalso the zeolite P-type as described in EP-A-0,384,070.

In particular, the composition may contain any one of the organic andinorganic builder materials, though, for environmental reasons,phosphate builders are preferably omitted or only used in very smallamounts.

Typical builders usable in the present invention are, for example,sodium carbonate, calcite/carbonate, the sodium salt of nitrilotriaceticacid, sodium citrate, carboxymethyloxy malonate, carboxymethyloxysuccinate and water-insoluble crystalline or amorphous aluminosilicatebuilder materials, each of which can be used as the main builder, eitheralone or in admixture with minor amounts of other builders or polymersas co-builder.

It is advantageous for the compositions of the invention to comprise atleast one nitrogen-containing, dye binding, DTI polymers. Of thesepolymers and co-polymers of cyclic amines such as vinyl pyrrolidone,and/or vinyl imidazole are preferred. Suitable polymers includepolyvinyl pyrrolidone polymers, polyamine N-oxide polymers, copolymersof N-vinylpyrrolidone and N-vinylimidazole, and polymers ofN-carboxymethyl-4-vinylpyridinium chloride. Most preferably thecomposition according to the present invention comprises a dye transferinhibition agent selected from poly vinyl-pyrridine N-oxide (PVPy-NO),polyvinyl pyrrolidone (PVP), polyvinyl imidazole, N-vinylpyrrolidone andN-vinylimidazole copolymers (PVP/PVI), copolymers thereof, and mixturesthereof.

The amount of dye transfer inhibition agent in the composition accordingto the present invention will be from 0.01 to 10%, preferably from 0.02to 5%, more preferably from 0.03 to 2%, by weight of the composition.

Apart from the components already mentioned, the composition can containany of the conventional additives in amounts of which such materials arenormally employed in fabric washing detergent compositions.

Examples of these additives include;

-   -   buffers such as carbonates;    -   lather boosters, such as alkanolamides, particularly the        monoethanol amides derived from palmkernel fatty acids and        coconut fatty acids;    -   lather depressants, such as alkyl phosphates and silicones;    -   anti-redeposition agents, such as sodium carboxymethyl cellulose        and alkyl or substituted alkyl cellulose ethers;    -   stabilisers, such as phosphonic acid derivatives (i.e. Dequest®        types);    -   fabric softening agents;    -   inorganic salts and alkaline buffering agents, such as sodium        sulphate and sodium silicate;    -   and, usually in very small amounts, fluorescent agents;        perfumes; enzymes, such as proteases, cellulases, lipases,        amylases and oxidases; germicides and colourants.

In order that the invention may be further and better understood it willbe described in detail with reference to following non-limiting examplesand with reference to the accompanying figures wherein:

FIG. 1 shows absorbance vs. time for bleaching of a pure dye insolution.

EXAMPLES

The catalyst referred to in the examples is the Fe complex of3,4,8,9-tetrahydro-3,3,6,6,9,9-hexamethyl-1H-1,4,8,11-benzotetraazocyclotri-decane-2,5,7,10(6H, 11H) tetrone, with lithium as the counter-ion and water as theaxial ligand.

This was synthesised in accordance with the method set out in ourco-pending patent application GB 0020846.2.

FIG. 1 shows results in which with the conditions otherwise fixed, thesurfactant type is varied. Conditions were: 1 uM catalyst, 1000 uM H₂O₂,50 uM Dye 1 (arylazonaphthol dye, pure), 25° C., pH 10 borax buffer,+/−2 g/L surfactant.

The surfactants used were:

-   -   ‘C12ABS’: average C12 chain commercial alkylbenzene sulfonate        ‘purified’ ex Aldrich    -   ‘C12E5’: a pure ethoxylated alcohol, and,    -   ‘DTAC’: dodecyl trimethylammonium chloride.

A control was performed in which water was used instead of thesurfactant.

The catalyst solution is added to system at t=2 min and H₂O₂ at t=6 min.In the example with ABS no H₂O₂ was added at all, since the colour hadalready gone.

As will be noted from the figure, with both water or pure nonionic andcationic surfactants there was no significant bleaching by catalyst inabsence of H₂O₂. In each of these cases the dyes was bleached over ashort period (less than a minute) once the hydrogen peroxide was added.

In the case of the ABS surfactant, bleaching of the dye commenced assoon as the dye was added, i.e. before the addition of peroxide.Bleaching of the dye reached an end point after around six minutes.

1. A bleaching composition comprising: a) an alkyl benzene sulphonatesurfactant, and b) a macrocyclic tetra amido N-donor metal ligandcomplex, having the structure as shown below:

wherein: B₁, B₃ and B₄ each represent a bridging group having zero, onetwo or three carbon containing nodes for substitution, and B₂ representsa bridging group having at least one carbon containing node forsubstitution, each said node containing a C(R), C(R₁)(R₂) or C(R)₂, eachR substituent is the same or different from the remaining Rsubstituents, and (1) is selected from the group consisting of alkyl,alkenyl, cycloalkyl, cycloalkenyl, aryl, alkynyl, alkylaryl, halogen,alkoxy, phenoxy and combinations thereof, or (2) form a substituted orunsubstituted benzene ring of which two carbons on the ring form nodesin the B-unit; M is a transition metal ion: L is an axial ligand; and. Qis an alkali metal or tetra-alkyl ammonium or tetra-phenyl phosphoniumcounter-ion and. said composition being substantially devoid of anyadded peroxygen bleach or a peroxy based or peroxyl-generating bleachsystem.
 2. A bleaching composition according to claim 1 wherein thealkyl benzene sulphonate surfactant is present in the composition in anamount sufficient to provide a concentration in a wash liquor of atleast 0.05 g/l.
 3. A bleaching composition according to claim 1, whereinthe macrocyclic tetra-amido N-donor metal-ligand complex catalyst ispresent in the composition in an amount sufficient to provide aconcentration in a wash liquor of 0.005 μm to 100 μm.
 4. cancelled
 5. Ableaching composition according to claim 1 wherein the axial ligand isselected from the group consisting of water and halide.
 6. A bleachingcomposition according to claim 1, wherein M is selected from the groupconsisting of Fe, Mn, Cr, Cu, Co, Ni, Mo, V, Zn and W.
 7. A bleachingcomposition according to claim 1 wherein the ligand is5,6-benzo-3,8,11,13-tetraoxo-2,2,9,9,12,12-hexamethyl-1,4,7,10-tetraaza-cyclo-tridecane.